Canals

White was an engineer who helped to build the first canal to bring coal to Philadelphia via the Lehigh River and the first wire suspension bridge. His collection includes letters (both personal and business related), journals, financial information, and business papers.

Dams

Hetzel was a professor of engineering at Haverford and an amateur photographer. He was deeply involved with Seneca protests over the flooding of their land due to the construction of the Kinzua Dam in the 1950s and 1960s.